• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

AC filament and ground

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Hi, with AC filament, which way would you use for grounding and reason (if any)?
1) ground one end of the filament.
2) connect each end of filament with a resistor to ground (virtual ground).
It seems to me either way does reduce hum, I just wonder which way is safer.
Thanks
 
Never leave a heater circuit floating; it must have a DC reference. No electrode within a valve envelope should be left floating.

Grounding one side is simple and often sufficient.

Grounding a centre-tap (either via a CT secondary or a pair of resistors or a humdinger pot) can give less hum.

Both ways are 'safe' as there is no personal danger to be protected from.
 
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